The present invention relates generally to semiconductor sensor devices and, more particularly, to a package-in-package semiconductor pressure sensor.
Semiconductor sensor devices, such as pressure sensors, are well known. Each such device contains a semiconductor pressure-sensing die. The pressure-sensing die is susceptible to mechanical damage during packaging and environmental damage when in use, and thus must be carefully packaged. Further, a pressure-sensing die, such as a piezo-resistive transducer or a parameterized layout cell (P-cell), does not allow full encapsulation because that would impede its functionality.
A conventional packaged semiconductor sensor device has a pressure-sensing die, possibly an acceleration-sensing die (G-cell), and a micro controller unit (MCU) die mounted to a substrate, electrically connected to package leads with bond wires, and covered by a pressure-sensitive gel, which enables the pressure of the ambient atmosphere to reach the pressure-sensitive active region on the top side of pressure-sensing die, while protecting all of the dies and the bond wires from mechanical damage during packaging and environmental damage (e.g., contamination and/or corrosion) when in use. The die/substrate assembly is encased in molding compound and covered by a metal lid having a vent hole that exposes the gel-covered pressure-sensing die to ambient atmospheric pressure outside the sensor device.
One problem with the design of conventional pressure sensors is the high manufacturing cost due to the pre-molded package base, the metal lid, and the large volume of pressure-sensitive gel. Accordingly, it would be advantageous to have a more economical way to package pressure-sensing dies in semiconductor sensor devices.